LONDON, March 27 (Reuters) - A top index of pan-European shares was set for its biggest weekly drop of the year on Friday, although it snapped a sharp two-day losing streak following a surge in Danish pharmaceuticals firm Novo Nordisk.

By the close, the FTSEurofirst 300 index of top European shares was up 0.2 percent at 1,576.86 points, but down 2.1 percent for the week -- the biggest weekly drop for the index since December.

European stocks had tumbled in the previous two sessions, with the FTSEurofirst 300 losing 1.9 percent as a rebounding euro currency prompted investors to cash in recent sharp gains.

A similar pattern was seen on Friday, with the FTSEurofirst 300 giving up some early gains as the euro recovered from an early drop to trade 0.3 percent higher.

European shares have rallied in the past six months as investors bet a sharp drop in the currency would boost the region's economy and lift corporate results.

This week's drop is only the third weekly fall for the FTSEurofirst 300 this year, as the euro has dropped about 20 percent against the dollar over the past year. This is set to give euro zone companies a major lift as roughly 50 percent of their earnings come from outside the region.

The single currency retreated on prospects of a quantitative easing campaign from the European Central Bank, launched this month, contrasting with the trajectory of monetary policy in the United States where the Federal Reserve is seen raising interest rates this year.

"The weaker currency has been very beneficial for the exporters ... Perhaps the euro fell too quickly, and we've seen a pull back in the dollar in recent weeks," said James Butterfill, global equity strategist at Coutts.

"However, it's likely in the longer term that the euro continues to weaken, which will benefit many of the large caps in Europe that have the greatest foreign revenue exposure."

Novo Nordisk jumped 10.4 percent after it said it would submit interim data from a clinical trial of its new insulin drug Tresiba to U.S. regulators within the next month.

"Because the company's medium-term growth projections depend on U.S. Tresiba this is a positive for sentiment," analysts at Barclays said in a note.

Sports retailer Adidas rose 2.8 percent to a nine-month high after a bullish investor day, with a couple of brokers upgrading their target price on the stock.

Mining shares bucked the trend on Friday, with Glencore and Anglo American both falling 3 percent.

An industry official said three-quarters of China's domestic iron ore capacity was incurring losses, as a sustained slump in the price of the steelmaking commodity batters higher-cost producers.